power: qpnp-smbcharger: add support for hvdcp_3 properties

Implement properties to realize authentication and optimization
of hvdcp3 charger.

The steps to prepare include, among other steps:
-disabling HVDCP and APSD
-reducing input current to 500mA
-faking a removal and insertion

The steps to unprepare include, among other steps:
-re-enable HVDCP and APSD.
-reset the input current limit.
-faking a removal and insertion.

Note that if the charger is removed, prepare or pulsing state need to
be reset.

Change-Id: I529e1515274088a3d540e9296681d4e6709654a4
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>